172 research outputs found

    Phytochemical Diversity in Essential Oil of Vitex negundo L. Populations from India

    Get PDF
    Vitex negundo L., commonly known as the ‘Nirgundi’ has a long history of medicinal use in traditional and folk medicines for various diseases. To explore the diversity of the essential oil yield and composition of V. negundo, 23 populations were collected during spring season from the western Himalayan region. The essential oil yields varied from 0.06 to 0.10% in different populations of V. negundo. GC-FID, GC-MS, and statistical analysis of the leaf volatile oils showed significant phytochemical diversity. The volatiles of V. negundo were complex mixtures of 61 constituents, with sabinene (2.8-40.8%), viridiflorol (10.7%-23.8%), β-caryophyllene (5.3-21.4%), terpinen-4-ol (0.1-7.2%), epi-laurenene (2.2-5.9%), humulene epoxide II (0.5-4.6%), and abietadiene (0.1%-4.3%) as major constituents. Based on the distribution of major constituents, four groups were noticed by the multidimensional scaling and hierarchical average linkage cluster analyses. In conclusion, the yield and composition of the essential oils isolated from V. negundo varied considerably, depending on the origin

    INTEROPERABLE MODEL FOR BIORESOURCE DISTRIBUTED DATABASES

    Get PDF
    Recently, numerous frameworks and tools are being developed for enhancing access to data and services with a standardized view to communicate the advances in open information sharing. Another emerging field of data exploration is encountered in the coordination, examination and perception of bioresource data and are prompting corresponding new innovations. The bioresource information team aims to develop standards for nationwide data exchange by the establishment of a catalog service to locate and access biological data and information from across the country and information tool for decision makers. With the growth of open data sharing initiatives, the sharing of data among different and myriad sources has increased significantly, but major challenge lies in addressing the issues of interoperability during exchange and use since the data sources are heterogeneous and the data being organization specific is prepared with different (organization) specific data standards and platforms. This paper presents the model based on the study of different metadata standards and to develop a recommended standard for biodiversity information to support interoperability among heterogeneous databases under the umbrella of Indian Bioresource Information Network (IBIN) portal. The paper presents the mapping of different data standards into the IBIN standard for sharing species data in the form of distributed and interoperable web services to set the stage for interoperability

    Evaluation of harvesting time and standardization of distillation duration for higher essential oil content and quality in German chamomile (Chamomilla recutita L.)

    Get PDF
    Essential oil yield and composition in aromatic crops might be affected by genetic, agronomical and environmental factors but till date there is no clear information about the harvesting time and distillation for higher essential oil content without affecting quality. The current study was carried out to evaluate harvesting of chamomile flowers without herb and with herb part at three different times (6 A.M., 12 P.M. and 6 P.M.) and four distillation treatments (3 h, 4 h, 5 h & 6 h) for dried chamomile flowers. Results indicated that essential oil content was more in chamomile flowers without herb (0.15-0.18%) as compared to flowers with herb (0.06-0.09%). Essential oil content in chamomile flowers without herb was found statistically at par at harvest time of 12 P.M. (0.18%) and 6 P.M. (0.18%) and significantly higher than harvesting time of 6 A.M. (0.15%). Essential oil of chamomile flowers without herb contained maximum α-bisabolol oxide-B, (Z)-spiroether, and chamazulene at 12 P.M. and 6 P.M. while, α-bisabolone oxide-A and α-bisabolol oxide-A were maximum at 6 A.M. and (E)-β-farnesene was more at 12 P.M. Similarly, in distillation experiment, higher oil content was observed in chamomile dried flowers which were hydro-distilled for 6 h (1.20%) compared to other hydro-distillation durations. Marker compounds i.e. α-bisabolol oxide-A, α-bisabolone oxide-A, α-bisabolol oxide-B, (E)-β-farnesene and chamazulene were more at 5 h and 6 h distillation duration while (Z)-spiroether was more at 3 h distillation duration. The present study showed that in order to obtain higher essential oil, flowers without herb harvested at 12 P.M or 6 P.M. should be subjected to 5-6 h hydro-distillation

    Quaternary borocarbides: New class of intermetallic superconductors

    Get PDF
    Our recent discovery of superconductivity (SC) in the four-element multiphase Y-Ni-B-C system at an elevated temperature (TC approximately 12 K) has opened up great possibilities of identifying new superconducting materials and generating new physics. Superconductivity with Tc (greater than 20 K) higher than that known so far in bulk intermetallics has been observed in multiphase Y-Pd-B-C and Th-Pd-B-C systems and a family of single phase materials RENi2B2C (RE= Y, rare earth) have been found. Our investigations show YNi2B2C to be a strong coupling hard type-II SC. HC2(T) exhibits an unconventional temperature dependence. Specific heat and magnetization studies reveal coexistence of SC and magnetism in RNi2B2C (R = Ho, Er, Tm) with magnetic ordering temperatures (Tc approximately 8 K, 10.5 K, 11 K and Tm approximately 5 K, approximately 7K, approximately 4 K respectively) that are remarkably higher than those in known magnetic superconductors . Mu-SR studies suggest the possibility of Ni atoms carrying a moment in TmNi2B2C. Resistivity results suggests a double re-entrant transition (SC-normal-SC) in HoNi2B2C. RENi2B2C (RE = Ce, Nd, Gd) do not show SC down to 4.2 K. The Nd- and Gd-compounds order magnetically at approximately 4.5 K and approximately 19.5 K, respectively. Two SC transitions are observed in Y-Pd-B-C (Tc approximately 22 K, approximately 10 K) and in Th-Pd-B-C (Tc approximately 20 K, approximately 14 K) systems, which indicate that there are at least two structures which support SC in these borocarbides. In our multiphase ThNi2B2C we observe SC at approximately 6 K. No SC was seen in multiphase UNi2B2C, UPd2B2C, UOs2Ge2C and UPd5B3C(0.35) down to 4.2 K. Tc in YNi2B2C is depressed by substitutions (Gd, Th and U at Y-sites and Fe, Co at Ni-sites)

    Reanalysis of two eclipsing binaries: EE Aqr and Z Vul

    Full text link
    We study the radial-velocity and light curves of the two eclipsing binaries EE Aqr and Z Vul. Using the latest version of the Wilson & Van Hamme (2003) model, absolute parameters for the systems are determined. We find that EE Aqr and Z Vul are near-contact and semi-detached systems, respectively. The primary component of EE Aqr fills about 96% of its 'Roche lobe', while its secondary one appears close to completely filling this limiting volume. In a similar way, we find fill-out proportions of about 72 and 100% of these volumes for the primary and secondary components of Z Vul respectively. We compare our results with those of previous authors.Comment: 13 pages, 8 figures, 10 table

    Relationship Between Preexisting Cardiovascular Disease and Death and Cardiovascular Outcomes in Critically Ill Patients With COVID-19

    Get PDF
    BACKGROUND: Preexisting cardiovascular disease (CVD) is perceived as a risk factor for poor outcomes in patients with COVID-19. We sought to determine whether CVD is associated with in-hospital death and cardiovascular events in critically ill patients with COVID-19. METHODS: This study used data from a multicenter cohort of adults with laboratory-confirmed COVID-19 admitted to intensive care units at 68 centers across the United States from March 1 to July 1, 2020. The primary exposure was CVD, defined as preexisting coronary artery disease, congestive heart failure, or atrial fibrillation/flutter. Myocardial injury on intensive care unit admission defined as a troponin I or T level above the 99th percentile upper reference limit of normal was a secondary exposure. The primary outcome was 28-day in-hospital mortality. Secondary outcomes included cardiovascular events (cardiac arrest, new-onset arrhythmias, new-onset heart failure, myocarditis, pericarditis, or stroke) within 14 days. RESULTS: Among 5133 patients (3231 male [62.9%]; mean age 61 years [SD, 15]), 1174 (22.9%) had preexisting CVD. A total of 1178 (34.6%) died, and 920 (17.9%) had a cardiovascular event. After adjusting for age, sex, race, body mass index, history of smoking, and comorbidities, preexisting CVD was associated with a 1.15 (95% CI, 0.98-1.34) higher odds of death. No independent association was observed between preexisting CVD and cardiovascular events. Myocardial injury on intensive care unit admission was associated with higher odds of death (adjusted odds ratio, 1.93 [95% CI, 1.61-2.31]) and cardiovascular events (adjusted odds ratio, 1.82 [95% CI, 1.47-2.24]), regardless of the presence of CVD. CONCLUSIONS: CVD risk factors, rather than CVD itself, were the major contributors to outcomes in critically ill patients with COVID-19. The occurrence of myocardial injury, regardless of CVD, and its association with outcomes suggests it is likely due to multiorgan injury related to acute inflammation rather than exacerbation of preexisting CVD. REGISTRATION: NCT04343898; https://clinicaltrials.gov/ct2/show/NCT04343898

    CNx-modified Fe3O4 as Pt nanoparticle support for the oxygen reduction reaction

    Get PDF
    A novel electrocatalyst support material, nitrogendoped carbon (CNx)-modified Fe3O4 (Fe3O4-CNx), was synthesized through carbonizing a polypyrrole-Fe3O4 hybridized precursor. Subsequently, Fe3O4-CNx-supported Pt (Pt/Fe3O4-CNx) nanocomposites were prepared by reducing Pt precursor in ethylene glycol solution and evaluated for the oxygen reduction reaction (ORR). The Pt/Fe3O4-CNx catalysts were characterized by X-ray diffraction, Raman spectra, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electrocatalytic activity and stability of the as-prepared electrocatalysts toward ORR were studied by cyclic voltammetry and steady-state polarization measurements. The results showed that Pt/ Fe3O4-CNx catalysts exhibited superior catalytic performance for ORR to the conventional Pt/C and Pt/C-CNx catalysts.Web of Scienc

    Local structure study about Co in YBa2_2(Cu1−x_{1-x}Cox_x)3_3O7−δ_{7-\delta} thin films using polarized XAFS

    Full text link
    We have studied the local structure around Co in YBa2_2(Cu1−x_{1-x}Cox_x)3_3O7−δ_{7-\delta} thin films with three different concentrations: x=0.07, 0.10, 0.17, and in a PrBa2_2(Cu1−x_{1-x}Cox_x)3_3O7−δ_{7-\delta} thin film of concentration x=0.05 using the X-ray Absorption Fine Structure (XAFS) technique. Data were collected at the Co KK-edge with polarizations both parallel and perpendicular to the film surface. We find that the oxygen neighbors are well ordered and shortened in comparison with YBCO Cu-O values to 1.80 \AA{} and 1.87 \AA{} in the cc-axis and abab-plane, respectively. A comparison of further neighbors in the thin film and powder data show that these peaks in the film are suppressed in amplitude relative to the powder samples, which suggests there is more disorder and/or distortions of the Co environment present in the thin films.Comment: 14 pages; To be submitted to Phys. Rev.

    Role and task allocation framework for Multi-Robot Collaboration with latent knowledge estimation

    Get PDF
    In this work a novel framework for modeling role and task allocation in Cooperative Heterogeneous Multi-Robot Systems (CHMRSs) is presented. This framework encodes a CHMRS as a set of multidimensional relational structures (MDRSs). This set of structure defines collaborative tasks through both temporal and spatial relations between processes of heterogeneous robots. These relations are enriched with tensors which allow for geometrical reasoning about collaborative tasks. A learning schema is also proposed in order to derive the components of each MDRS. According to this schema, the components are learnt from data reporting the situated history of the processes executed by the team of robots. Data are organized as a multirobot collaboration treebank (MRCT) in order to support learning. Moreover, a generative approach, based on a probabilistic model, is combined together with nonnegative tensor decomposition (NTD) for both building the tensors and estimating latent knowledge. Preliminary evaluation of the performance of this framework is performed in simulation with three heterogeneous robots, namely, two Unmanned Ground Vehicles (UGVs) and one Unmanned Aerial Vehicle (UAV)
    • …
    corecore